Syringe and needle assemblies have been used for a number of years for the purpose of injecting fluids into or withdrawing fluids from a body. These fluids may include medicine, blood or other types of biological materials. Due to the multitude of infectious diseases which may be carried by bodily fluids such as blood, it is extremely important that any potential leakage of fluid during an injection or withdrawal process be kept to an absolute minimum.
One location in a delivery/extraction system where bodily fluids and/or other substances may leak from the system is the connection area between the syringe and the needle assembly. Because syringes and needle assemblies are often marketed and/or manufactured separately, a doctor, nurse or other technician is required to properly connect the needle assembly to the syringe. If the needle assembly is not properly connected to the syringe, the possibility of a poor connection and accidental leakage of biological materials increases significantly. This correspondingly increases the risk of exposure to hazardous materials.
The type of fluid or other biological media being delivered to or from the syringe may also contain materials, components, or ingredients (hereinafter, “material”) that can separate at a poor connection when exposed to the injection pressures developed in the syringe. The material separation can cause further problems of injecting or extracting the full contents of the syringe through the needle. A needle assembly properly connected to the syringe would significantly reduce the possibility of material, component, or ingredient separation from occurring.
A variety of mechanisms have been developed to securely fasten needle assemblies to syringes, but each have their drawbacks. For example, a number of conventional mechanisms include a linear connection between the syringe and the needle assembly in the form of a track or groove, in which the needle assembly slides onto the syringe. Systems with linear connections often include o-ring type seals that are located a certain distance from the path of the fluid material. This distance between the seal and the material pathway may cause delivery and/or extraction problems for certain types of materials. Other types of conventional systems involve a rotational fitting between the needle assembly and the syringe. These systems allow for a line-to-line seal that is integral to the material path, but the systems are somewhat limited in their ability to indicate to the user when an adequate or proper connection has been achieved. Furthermore, some of these systems may be prone to being “overtightened” which can affect the functionality and/or safety of the completed assembly. Also, it often can be difficult to determine whether the needle assembly is properly connected to the syringe. In whichever case, an improperly made connection between the needle assembly and the syringe can have hazardous results and/or functional/operational problems.
Additionally, most conventional injection needles do not provide a mechanism for adequately tightening the needle to a standard luer syringe without the use of tools by the user. A few products currently available provide a double grip design in order to produce an increased leverage, but double grip designs typically expect that the user will rotate the needle relative to the syringe. Tightening the needle relative to syringe can cause additional tissue trauma if the needle is in the tissue. Some designs also do not permit for the repeated connection and disconnection of the needle with different syringes, as the needle's plastic luer threads tend to distort or wear under the required tightening force. Furthermore, some delivery and extraction systems do not provide a sufficiently tight seal between the syringe and needle luer connections or a connection that clears particles from the luer surface of the syringe.
Finally, conventional injection needles do not provide a mechanism by which to adequately tighten the needle to a standard luer syringe using the sheath assembly. Having such ability would help to prevent needle stick injuries through the placement of the handle on an axis that is offset from the needle tip.